The present invention relates to a retaining ring structure. The retaining ring structure of the present invention may be used in a variety of different devices to retain one member from axial movement relative to another member. The retaining ring structure of the present invention is constructed such that a minimum of deformation of the member in which the retaining ring is located occurs, and yet the retaining ring structure is capable of resisting substantial forces tending to effect relative movement of the members.
Retaining rings under appreciable thrust load, tend to "dish" or tilt in the groove in which they are located. This can result in (1) plastic flow of the material of the member having the circumferential groove, (2) deformation of the retaining ring, and/or (3) the retaining ring being completely removed from the groove. Plastic flow of the material of the member having the groove results in a lip being produced on the edge of the retaining ring groove. Plastic flow of the groove wall may lead to failure of the assembly due to the inability of the retaining ring to resist the load, and/or the lip may make disassembly of the device in which the ring is used difficult.
Thus, one principal object of the present invention is to provide a retaining ring structure which minimizes the concentration of stresses normally occurring at the edge of the retaining ring groove, and distributes the load to regions better able to withstand such forces and without deformation of the edge of the retaining ring groove. Rather than bearing against the edge of the groove as is common with current retaining ring structures, the retaining ring structure of the present invention bears for the most part on the sidewall defining the groove at a region spaced from the circumferential edge of the groove.
Further, the ring structures of the present invention include means to minimize dishing or rocking of the ring in the groove and maximize the load bearing capacity of the ring without substantial deformation. This is accomplished by a structure which applies the thrust load to the ring in the groove at a location immediately adjacent the surface of the member having the groove. As a result, the forces acting to rock or dish the ring in the groove act through a minimum moment arm. Thus, for a given thrust load the tendency for the ring in the groove to rock or deform is minimized. The structure which accomplishes this is a ring segment which is associated with the ring segment located in the groove and applies the thrust load to the ring segment in the groove immediately adjacent the surface of the member in which the groove is located.
Further, in one embodiment means are provided to limit collapse of the retaining ring structure and unintentional disengagement of the ring structure from the groove. This is accomplished by a ring segment which has surfaces which abut when the ring segment in the groove circumferentially contracts to a predetermined extent. The abutting surfaces limit such contraction and thus reduce the possibility of unintentional removal of the ring structure from the groove.
A retaining ring structure of the present invention preferably comprises a pair of L-shaped ring segments in concentric and nested relationship with the outer apex of the inner ring segment located at or near the inner apex of the outer ring segment, or in other cases, with the outer apex of the outer ring segment located at or near the inner apex of the inner ring segment. This structure may be achieved in two ways; i.e., with two separate ring segments of L-shaped cross section nested on one another, or by means of a spiraliform structure having two L-shaped sector ring segments as overlapping convolutions and in nested relationship with a compound transition portion joining the inner and outer ring segments.